Six Sigma (or the Six Sigma methodology) is a business problem solving methodology and a measure of quality control that strives for near perfection. Six Sigma is a disciplined, data-driven approach and methodology for eliminating defects (driving towards six standard deviations between the mean and the nearest specification limit) in any process—from manufacturing to transactional and from product to service. The statistical representation of Six Sigma describes quantitatively how a process is performing. To achieve Six Sigma level, a process must not produce more than 3.4 defects per million opportunities, where a Six Sigma defect is defined as anything outside desired specifications, and a Six Sigma opportunity is the total quantity of chances for a defect.
The fundamental objective of the Six Sigma methodology is the implementation of a measurement-based strategy that focuses on process improvement and variation reduction through the application of Six Sigma improvement projects. This is accomplished through the use of two Six Sigma sub-methodologies: DMAIC and DMADV. The Six Sigma DMAIC process (define, measure, analyze, improve, control) is an improvement system for existing processes failing to meet the customer's requirements (internal or external) and looking for incremental improvement. The Six Sigma DMADV process (define, measure, analyze, design, verify) is an improvement system used to develop new processes or products at Six Sigma quality levels and may also be employed if a current process requires more than incremental improvement.
FIG. 1 is a flow chart showing a typical inspection receiving process 100 of outsourced subassemblies, parts, and materials used by a manufacturer (e.g., a data storage device manufacturer, and the like). The process 100 may have many deficiencies. The process 100 may start with step 102, in which control methods are established for an outsourced product (e.g., a subassembly, a part, a material, and the like) not conforming to specified requirements. The deficiency of this step 102 lies in the fact that conventionally there is no online SPC (Statistical Process Control) to detect or monitor the trend of non-conformance. Then, a substandard product is reported to authorized personnel for disposition 104. However, in the step 104, inaccurate disposition by authorized personnel may prevent the true root cause from being identified since the authorized personnel lack SPC information on non-conforming products. Next, a report may be prepared to include specifications that provide discrepant material reports, Notice of product Variance, and/or Material Review Board disposition 106. However, in the step 106, there may be little or no ready access to historical reject trends, root causes, or non-conformance of past products. Then, a substandard product is identified and segregated 108. Next, the substandard product is disposed 110. In the steps 108 and 110, however, there may be potential delay and time lag while awaiting a second disposition, which may lead to breakdown in the continuity of the reject process. Then the substandard product may be reworked, accepted without repair, scrapped, re-graded (reclassified from a high grade to a low grade), or returned 112. Next, the corrective action is determined and documented based on the root cause of the failure(s) 114. However, in the steps 112 and 114, returning or charging non-conforming products may lead to a reactive approach for incoming quality. Both real and opportunity costs may be associated with returns and charge backs. Then, Material Review Board outlines a method of recovery or eliminates a non-conforming incoming product 116. However, in the step 116, the vendor may rework and correct problems, but no tracking of future quality is instigated for initial non-conformance. Thus, there may be a potential for continuing non-conformance of incoming products.
Thus, it would be desirable to provide a method and apparatus for integrating the Six Sigma methodology into an inspection receiving process of outsourced subassemblies, parts, and materials: acceptance, rejection, trending and tracking.